/**
 * 
 */
package com.baidu.unbiz.common.apache;

import java.lang.reflect.AccessibleObject;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.Collection;

import com.baidu.unbiz.common.ArrayUtil;

/**
 * 
 * @author <a href="mailto:xuchen06@baidu.com">xuc</a>
 * @version create on 2014年9月15日 上午5:38:29
 */
public class EqualsBuilder {
    /**
     * If the fields tested are equals. The default value is <code>true</code>.
     */
    private boolean isEquals = true;

    /**
     * <p>
     * Constructor for EqualsBuilder.
     * </p>
     * 
     * <p>
     * Starts off assuming that equals is <code>true</code>.
     * </p>
     * 
     * @see Object#equals(Object)
     */
    public EqualsBuilder() {
        // do nothing for now.
    }

    // -------------------------------------------------------------------------

    /**
     * <p>
     * This method uses reflection to determine if the two <code>Object</code>s are equal.
     * </p>
     * 
     * <p>
     * It uses <code>AccessibleObject.setAccessible</code> to gain access to private fields. This means that it will
     * throw a security exception if run under a security manager, if the permissions are not set up correctly. It is
     * also not as efficient as testing explicitly.
     * </p>
     * 
     * <p>
     * Transient members will be not be tested, as they are likely derived fields, and not part of the value of the
     * Object.
     * </p>
     * 
     * <p>
     * Static fields will not be tested. Superclass fields will be included.
     * </p>
     * 
     * @param lhs <code>this</code> object
     * @param rhs the other object
     * @return <code>true</code> if the two Objects have tested equals.
     */
    public static boolean reflectionEquals(Object lhs, Object rhs) {
        return reflectionEquals(lhs, rhs, false, null, null);
    }

    /**
     * <p>
     * This method uses reflection to determine if the two <code>Object</code>s are equal.
     * </p>
     * 
     * <p>
     * It uses <code>AccessibleObject.setAccessible</code> to gain access to private fields. This means that it will
     * throw a security exception if run under a security manager, if the permissions are not set up correctly. It is
     * also not as efficient as testing explicitly.
     * </p>
     * 
     * <p>
     * Transient members will be not be tested, as they are likely derived fields, and not part of the value of the
     * Object.
     * </p>
     * 
     * <p>
     * Static fields will not be tested. Superclass fields will be included.
     * </p>
     * 
     * @param lhs <code>this</code> object
     * @param rhs the other object
     * @param excludeFields Collection of String field names to exclude from testing
     * @return <code>true</code> if the two Objects have tested equals.
     */
    public static boolean reflectionEquals(Object lhs, Object rhs, Collection /* String */<String> excludeFields) {
        return reflectionEquals(lhs, rhs, ReflectionToStringBuilder.toNoNullStringArray(excludeFields));
    }

    /**
     * <p>
     * This method uses reflection to determine if the two <code>Object</code>s are equal.
     * </p>
     * 
     * <p>
     * It uses <code>AccessibleObject.setAccessible</code> to gain access to private fields. This means that it will
     * throw a security exception if run under a security manager, if the permissions are not set up correctly. It is
     * also not as efficient as testing explicitly.
     * </p>
     * 
     * <p>
     * Transient members will be not be tested, as they are likely derived fields, and not part of the value of the
     * Object.
     * </p>
     * 
     * <p>
     * Static fields will not be tested. Superclass fields will be included.
     * </p>
     * 
     * @param lhs <code>this</code> object
     * @param rhs the other object
     * @param excludeFields array of field names to exclude from testing
     * @return <code>true</code> if the two Objects have tested equals.
     */
    public static boolean reflectionEquals(Object lhs, Object rhs, String[] excludeFields) {
        return reflectionEquals(lhs, rhs, false, null, excludeFields);
    }

    /**
     * <p>
     * This method uses reflection to determine if the two <code>Object</code>s are equal.
     * </p>
     * 
     * <p>
     * It uses <code>AccessibleObject.setAccessible</code> to gain access to private fields. This means that it will
     * throw a security exception if run under a security manager, if the permissions are not set up correctly. It is
     * also not as efficient as testing explicitly.
     * </p>
     * 
     * <p>
     * If the TestTransients parameter is set to <code>true</code>, transient members will be tested, otherwise they are
     * ignored, as they are likely derived fields, and not part of the value of the <code>Object</code>.
     * </p>
     * 
     * <p>
     * Static fields will not be tested. Superclass fields will be included.
     * </p>
     * 
     * @param lhs <code>this</code> object
     * @param rhs the other object
     * @param testTransients whether to include transient fields
     * @return <code>true</code> if the two Objects have tested equals.
     */
    public static boolean reflectionEquals(Object lhs, Object rhs, boolean testTransients) {
        return reflectionEquals(lhs, rhs, testTransients, null, null);
    }

    /**
     * <p>
     * This method uses reflection to determine if the two <code>Object</code>s are equal.
     * </p>
     * 
     * <p>
     * It uses <code>AccessibleObject.setAccessible</code> to gain access to private fields. This means that it will
     * throw a security exception if run under a security manager, if the permissions are not set up correctly. It is
     * also not as efficient as testing explicitly.
     * </p>
     * 
     * <p>
     * If the testTransients parameter is set to <code>true</code>, transient members will be tested, otherwise they are
     * ignored, as they are likely derived fields, and not part of the value of the <code>Object</code>.
     * </p>
     * 
     * <p>
     * Static fields will not be included. Superclass fields will be appended up to and including the specified
     * superclass. A null superclass is treated as java.lang.Object.
     * </p>
     * 
     * @param lhs <code>this</code> object
     * @param rhs the other object
     * @param testTransients whether to include transient fields
     * @param reflectUpToClass the superclass to reflect up to (inclusive), may be <code>null</code>
     * @return <code>true</code> if the two Objects have tested equals.
     * @since 2.0
     */
    public static boolean reflectionEquals(Object lhs, Object rhs, boolean testTransients, Class<?> reflectUpToClass) {
        return reflectionEquals(lhs, rhs, testTransients, reflectUpToClass, null);
    }

    /**
     * <p>
     * This method uses reflection to determine if the two <code>Object</code>s are equal.
     * </p>
     * 
     * <p>
     * It uses <code>AccessibleObject.setAccessible</code> to gain access to private fields. This means that it will
     * throw a security exception if run under a security manager, if the permissions are not set up correctly. It is
     * also not as efficient as testing explicitly.
     * </p>
     * 
     * <p>
     * If the testTransients parameter is set to <code>true</code>, transient members will be tested, otherwise they are
     * ignored, as they are likely derived fields, and not part of the value of the <code>Object</code>.
     * </p>
     * 
     * <p>
     * Static fields will not be included. Superclass fields will be appended up to and including the specified
     * superclass. A null superclass is treated as java.lang.Object.
     * </p>
     * 
     * @param lhs <code>this</code> object
     * @param rhs the other object
     * @param testTransients whether to include transient fields
     * @param reflectUpToClass the superclass to reflect up to (inclusive), may be <code>null</code>
     * @param excludeFields array of field names to exclude from testing
     * @return <code>true</code> if the two Objects have tested equals.
     * @since 2.0
     */
    public static boolean reflectionEquals(Object lhs, Object rhs, boolean testTransients, Class<?> reflectUpToClass,
            String[] excludeFields) {
        if (lhs == rhs) {
            return true;
        }
        if (lhs == null || rhs == null) {
            return false;
        }
        // Find the leaf class since there may be transients in the leaf
        // class or in classes between the leaf and root.
        // If we are not testing transients or a subclass has no ivars,
        // then a subclass can test equals to a superclass.
        Class<?> lhsClass = lhs.getClass();
        Class<?> rhsClass = rhs.getClass();
        Class<?> testClass;
        if (lhsClass.isInstance(rhs)) {
            testClass = lhsClass;
            if (!rhsClass.isInstance(lhs)) {
                // rhsClass is a subclass of lhsClass
                testClass = rhsClass;
            }
        } else if (rhsClass.isInstance(lhs)) {
            testClass = rhsClass;
            if (!lhsClass.isInstance(rhs)) {
                // lhsClass is a subclass of rhsClass
                testClass = lhsClass;
            }
        } else {
            // The two classes are not related.
            return false;
        }
        EqualsBuilder equalsBuilder = new EqualsBuilder();
        try {
            reflectionAppend(lhs, rhs, testClass, equalsBuilder, testTransients, excludeFields);
            while (testClass.getSuperclass() != null && testClass != reflectUpToClass) {
                testClass = testClass.getSuperclass();
                reflectionAppend(lhs, rhs, testClass, equalsBuilder, testTransients, excludeFields);
            }
        } catch (IllegalArgumentException e) {
            // In this case, we tried to test a subclass vs. a superclass and
            // the subclass has ivars or the ivars are transient and
            // we are testing transients.
            // If a subclass has ivars that we are trying to test them, we get
            // an
            // exception and we know that the objects are not equal.
            return false;
        }
        return equalsBuilder.isEquals();
    }

    /**
     * <p>
     * Appends the fields and values defined by the given object of the given Class.
     * </p>
     * 
     * @param lhs the left hand object
     * @param rhs the right hand object
     * @param clazz the class to append details of
     * @param builder the builder to append to
     * @param useTransients whether to test transient fields
     * @param excludeFields array of field names to exclude from testing
     */
    private static void reflectionAppend(Object lhs, Object rhs, Class<?> clazz, EqualsBuilder builder,
            boolean useTransients, String[] excludeFields) {
        Field[] fields = clazz.getDeclaredFields();
        AccessibleObject.setAccessible(fields, true);
        for (int i = 0; i < fields.length && builder.isEquals; i++) {
            Field f = fields[i];
            if (!ArrayUtil.contains(excludeFields, f.getName()) && (f.getName().indexOf('$') == -1)
                    && (useTransients || !Modifier.isTransient(f.getModifiers()))
                    && (!Modifier.isStatic(f.getModifiers()))) {
                try {
                    builder.append(f.get(lhs), f.get(rhs));
                } catch (IllegalAccessException e) {
                    // this can't happen. Would get a Security exception instead
                    // throw a runtime exception in case the impossible happens.
                    throw new InternalError("Unexpected IllegalAccessException");
                }
            }
        }
    }

    // -------------------------------------------------------------------------

    /**
     * <p>
     * Adds the result of <code>super.equals()</code> to this builder.
     * </p>
     * 
     * @param superEquals the result of calling <code>super.equals()</code>
     * @return EqualsBuilder - used to chain calls.
     * @since 2.0
     */
    public EqualsBuilder appendSuper(boolean superEquals) {
        if (!isEquals) {
            return this;
        }
        isEquals = superEquals;
        return this;
    }

    // -------------------------------------------------------------------------

    /**
     * <p>
     * Test if two <code>Object</code>s are equal using their <code>equals</code> method.
     * </p>
     * 
     * @param lhs the left hand object
     * @param rhs the right hand object
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(Object lhs, Object rhs) {
        if (!isEquals) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null || rhs == null) {
            this.setEquals(false);
            return this;
        }
        Class<?> lhsClass = lhs.getClass();
        if (!lhsClass.isArray()) {
            // The simple case, not an array, just test the element
            isEquals = lhs.equals(rhs);
        } else if (lhs.getClass() != rhs.getClass()) {
            // Here when we compare different dimensions, for example: a
            // boolean[][] to a boolean[]
            this.setEquals(false);
        }
        // 'Switch' on type of array, to dispatch to the correct handler
        // This handles multi dimensional arrays of the same depth
        else if (lhs instanceof long[]) {
            append((long[]) lhs, (long[]) rhs);
        } else if (lhs instanceof int[]) {
            append((int[]) lhs, (int[]) rhs);
        } else if (lhs instanceof short[]) {
            append((short[]) lhs, (short[]) rhs);
        } else if (lhs instanceof char[]) {
            append((char[]) lhs, (char[]) rhs);
        } else if (lhs instanceof byte[]) {
            append((byte[]) lhs, (byte[]) rhs);
        } else if (lhs instanceof double[]) {
            append((double[]) lhs, (double[]) rhs);
        } else if (lhs instanceof float[]) {
            append((float[]) lhs, (float[]) rhs);
        } else if (lhs instanceof boolean[]) {
            append((boolean[]) lhs, (boolean[]) rhs);
        } else {
            // Not an array of primitives
            append((Object[]) lhs, (Object[]) rhs);
        }
        return this;
    }

    /**
     * <p>
     * Test if two <code>long</code> s are equal.
     * </p>
     * 
     * @param lhs the left hand <code>long</code>
     * @param rhs the right hand <code>long</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(long lhs, long rhs) {
        if (!isEquals) {
            return this;
        }
        isEquals = (lhs == rhs);
        return this;
    }

    /**
     * <p>
     * Test if two <code>int</code>s are equal.
     * </p>
     * 
     * @param lhs the left hand <code>int</code>
     * @param rhs the right hand <code>int</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(int lhs, int rhs) {
        if (!isEquals) {
            return this;
        }
        isEquals = (lhs == rhs);
        return this;
    }

    /**
     * <p>
     * Test if two <code>short</code>s are equal.
     * </p>
     * 
     * @param lhs the left hand <code>short</code>
     * @param rhs the right hand <code>short</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(short lhs, short rhs) {
        if (!isEquals) {
            return this;
        }
        isEquals = (lhs == rhs);
        return this;
    }

    /**
     * <p>
     * Test if two <code>char</code>s are equal.
     * </p>
     * 
     * @param lhs the left hand <code>char</code>
     * @param rhs the right hand <code>char</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(char lhs, char rhs) {
        if (!isEquals) {
            return this;
        }
        isEquals = (lhs == rhs);
        return this;
    }

    /**
     * <p>
     * Test if two <code>byte</code>s are equal.
     * </p>
     * 
     * @param lhs the left hand <code>byte</code>
     * @param rhs the right hand <code>byte</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(byte lhs, byte rhs) {
        if (!isEquals) {
            return this;
        }
        isEquals = (lhs == rhs);
        return this;
    }

    /**
     * <p>
     * Test if two <code>double</code>s are equal by testing that the pattern of bits returned by
     * <code>doubleToLong</code> are equal.
     * </p>
     * 
     * <p>
     * This handles NaNs, Infinities, and <code>-0.0</code>.
     * </p>
     * 
     * <p>
     * It is compatible with the hash code generated by <code>HashCodeBuilder</code>.
     * </p>
     * 
     * @param lhs the left hand <code>double</code>
     * @param rhs the right hand <code>double</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(double lhs, double rhs) {
        if (!isEquals) {
            return this;
        }
        return append(Double.doubleToLongBits(lhs), Double.doubleToLongBits(rhs));
    }

    /**
     * <p>
     * Test if two <code>float</code>s are equal byt testing that the pattern of bits returned by doubleToLong are
     * equal.
     * </p>
     * 
     * <p>
     * This handles NaNs, Infinities, and <code>-0.0</code>.
     * </p>
     * 
     * <p>
     * It is compatible with the hash code generated by <code>HashCodeBuilder</code>.
     * </p>
     * 
     * @param lhs the left hand <code>float</code>
     * @param rhs the right hand <code>float</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(float lhs, float rhs) {
        if (!isEquals) {
            return this;
        }
        return append(Float.floatToIntBits(lhs), Float.floatToIntBits(rhs));
    }

    /**
     * <p>
     * Test if two <code>booleans</code>s are equal.
     * </p>
     * 
     * @param lhs the left hand <code>boolean</code>
     * @param rhs the right hand <code>boolean</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(boolean lhs, boolean rhs) {
        if (!isEquals) {
            return this;
        }
        isEquals = (lhs == rhs);
        return this;
    }

    /**
     * <p>
     * Performs a deep comparison of two <code>Object</code> arrays.
     * </p>
     * 
     * <p>
     * This also will be called for the top level of multi-dimensional, ragged, and multi-typed arrays.
     * </p>
     * 
     * @param lhs the left hand <code>Object[]</code>
     * @param rhs the right hand <code>Object[]</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(Object[] lhs, Object[] rhs) {
        if (!isEquals) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null || rhs == null) {
            this.setEquals(false);
            return this;
        }
        if (lhs.length != rhs.length) {
            this.setEquals(false);
            return this;
        }
        for (int i = 0; i < lhs.length && isEquals; ++i) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Deep comparison of array of <code>long</code>. Length and all values are compared.
     * </p>
     * 
     * <p>
     * The method {@link #append(long, long)} is used.
     * </p>
     * 
     * @param lhs the left hand <code>long[]</code>
     * @param rhs the right hand <code>long[]</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(long[] lhs, long[] rhs) {
        if (!isEquals) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null || rhs == null) {
            this.setEquals(false);
            return this;
        }
        if (lhs.length != rhs.length) {
            this.setEquals(false);
            return this;
        }
        for (int i = 0; i < lhs.length && isEquals; ++i) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Deep comparison of array of <code>int</code>. Length and all values are compared.
     * </p>
     * 
     * <p>
     * The method {@link #append(int, int)} is used.
     * </p>
     * 
     * @param lhs the left hand <code>int[]</code>
     * @param rhs the right hand <code>int[]</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(int[] lhs, int[] rhs) {
        if (!isEquals) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null || rhs == null) {
            this.setEquals(false);
            return this;
        }
        if (lhs.length != rhs.length) {
            this.setEquals(false);
            return this;
        }
        for (int i = 0; i < lhs.length && isEquals; ++i) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Deep comparison of array of <code>short</code>. Length and all values are compared.
     * </p>
     * 
     * <p>
     * The method {@link #append(short, short)} is used.
     * </p>
     * 
     * @param lhs the left hand <code>short[]</code>
     * @param rhs the right hand <code>short[]</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(short[] lhs, short[] rhs) {
        if (!isEquals) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null || rhs == null) {
            this.setEquals(false);
            return this;
        }
        if (lhs.length != rhs.length) {
            this.setEquals(false);
            return this;
        }
        for (int i = 0; i < lhs.length && isEquals; ++i) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Deep comparison of array of <code>char</code>. Length and all values are compared.
     * </p>
     * 
     * <p>
     * The method {@link #append(char, char)} is used.
     * </p>
     * 
     * @param lhs the left hand <code>char[]</code>
     * @param rhs the right hand <code>char[]</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(char[] lhs, char[] rhs) {
        if (!isEquals) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null || rhs == null) {
            this.setEquals(false);
            return this;
        }
        if (lhs.length != rhs.length) {
            this.setEquals(false);
            return this;
        }
        for (int i = 0; i < lhs.length && isEquals; ++i) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Deep comparison of array of <code>byte</code>. Length and all values are compared.
     * </p>
     * 
     * <p>
     * The method {@link #append(byte, byte)} is used.
     * </p>
     * 
     * @param lhs the left hand <code>byte[]</code>
     * @param rhs the right hand <code>byte[]</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(byte[] lhs, byte[] rhs) {
        if (!isEquals) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null || rhs == null) {
            this.setEquals(false);
            return this;
        }
        if (lhs.length != rhs.length) {
            this.setEquals(false);
            return this;
        }
        for (int i = 0; i < lhs.length && isEquals; ++i) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Deep comparison of array of <code>double</code>. Length and all values are compared.
     * </p>
     * 
     * <p>
     * The method {@link #append(double, double)} is used.
     * </p>
     * 
     * @param lhs the left hand <code>double[]</code>
     * @param rhs the right hand <code>double[]</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(double[] lhs, double[] rhs) {
        if (!isEquals) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null || rhs == null) {
            this.setEquals(false);
            return this;
        }
        if (lhs.length != rhs.length) {
            this.setEquals(false);
            return this;
        }
        for (int i = 0; i < lhs.length && isEquals; ++i) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Deep comparison of array of <code>float</code>. Length and all values are compared.
     * </p>
     * 
     * <p>
     * The method {@link #append(float, float)} is used.
     * </p>
     * 
     * @param lhs the left hand <code>float[]</code>
     * @param rhs the right hand <code>float[]</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(float[] lhs, float[] rhs) {
        if (!isEquals) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null || rhs == null) {
            this.setEquals(false);
            return this;
        }
        if (lhs.length != rhs.length) {
            this.setEquals(false);
            return this;
        }
        for (int i = 0; i < lhs.length && isEquals; ++i) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Deep comparison of array of <code>boolean</code>. Length and all values are compared.
     * </p>
     * 
     * <p>
     * The method {@link #append(boolean, boolean)} is used.
     * </p>
     * 
     * @param lhs the left hand <code>boolean[]</code>
     * @param rhs the right hand <code>boolean[]</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(boolean[] lhs, boolean[] rhs) {
        if (!isEquals) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null || rhs == null) {
            this.setEquals(false);
            return this;
        }
        if (lhs.length != rhs.length) {
            this.setEquals(false);
            return this;
        }
        for (int i = 0; i < lhs.length && isEquals; ++i) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Returns <code>true</code> if the fields that have been checked are all equal.
     * </p>
     * 
     * @return boolean
     */
    public boolean isEquals() {
        return this.isEquals;
    }

    /**
     * Sets the <code>isEquals</code> value.
     * 
     * @param isEquals The value to set.
     * @since 2.1
     */
    protected void setEquals(boolean isEquals) {
        this.isEquals = isEquals;
    }

    /**
     * Reset the EqualsBuilder so you can use the same object again
     * 
     * @since 2.5
     */
    public void reset() {
        this.isEquals = true;
    }
}
